MODIS aerosol product at 3 km spatial resolution for urban and air quality studies

The MODerate resolution Imaging Spectroradiometer (MODIS) aboard the Terra and Aqua satellites has been producing an aerosol product since early 2000. The original product reports aerosol optical depth and a variety of other aerosol parameters at a spatial resolution of 10 km over both land and ocean. The 10 km product is actually constructed from 500 m pixels, which permits a strict selection process to choose the "best" or "cleanest" pixels in each 10 km square for use in the aerosol retrieval. Thus, the original 10 km product provides a useful product, accurate in many applications. However, the 10 km product can miss narrow aerosol plumes and the spatial variability associated with urban air pollution. The MODIS aerosol team will be introducing a finer resolution aerosol product over land regions in the next release of the product (Collection 6). The new product will be produced at 3 km resolution. It is based on the same procedures as the original product and benefits from the same spatial variability criteria for finding and masking cloudy pixels. The 3 km product does capture the higher spatial variability associated with individual aerosol plumes. However, it is noisier than the 10 km product. Both products will be available operationally in Collection 6. The new 3km product offers new synergistic possibilities with PM2.5 monitoring networks, AERONET and various air quality models such as CMAQ.